I don't know, I read all this stuff about don't let your chickens eat this don't let them do this and I wonder how much is based on true facts or is it just printed in a magizine or news paper or what ever to fill space or to sell copys. My chickens free range all the time and like our Tennessee friend says there has to be all kinds of poop in the area. We also have bears, bobcat, wild turkeys, coyotes, wolfves and dogs among the other smaller critters including large rats . I do take precautions though, I never bring a chicken in unless it's from a breeder I know is disease free or that I hatch out myself. I have had young chicks die and older chickens die for no apparent reason. I have good healthy chickens that give me plenty of eggs. Of course I feed them laying mash and starter/grower and give them a good healthy food, keep the pen clean and make sure they have plenty of clean water. We are on a well so I don't have to worry about chemicals in the water. I have raised chickens for a long time I keep doing what works and stop what doesn't work for me. And what I do doesn't mean it will work for someone else. But I have had good results with all my chickens over the years. Just my thoughts